If he's flirting with you online, but acting weird in person, it's really possible that he's just embarrassed to continue that kind of flirty relationship face-to-face.
Source: Shutter Stock I used to do this all the time with my crushes: I would find reasons to hang around them, even if I would never open my mouth. If he pops up everywhere you are, or always sits near you in class, but doesn't speak to you, it could mean that he's too shy to make the first move, so he's hoping you will.
Source: Shutter Stock When talking through Facebook messaging or texting, a shy guy may be able to open up enough to start flirting with you. A really shy guy would flirt with me for hours online, but when I saw him in class, he could barely make eye contact, let alone speak.
He’s also not going to openly flirt with you or try to get you to sext. I know this is a sign, because I used to do it all the time myself.That probably means he's super embarrassed that you caught him looking at you and doesn't know how to deal... If it happens a lot, it's a good sign that he's staring at you for a reason.Source: Shutter Stock This is another telltale sign.If you have repeatedly noticed the dude staring at you, then immediately looking away when you look at him, this could definitely mean that he likes you.Especially if he acts super weird afterwards, by which I mean avoiding your gaze entirely, walking away, or acting like you don't exist.